The advantages of a minimally invasive procedure, such as arthroscopy, as opposed to an open surgery, include less trauma to the patient, faster recovery time, shorter stays in expensive medical facilities, to name but a few. As a result, the use of these types of procedures has increased. Minimally invasive surgical procedures require the use of instruments that can be positioned and placed within the body through a small incision, requiring high precision while also being easy to maneuver and use. Among the many procedures performed using such minimally invasive procedures include the treatment of injuries such as torn cartilage or ligaments, requiring the fixation of soft tissue to bone for proper healing.
Traditionally, in order to ensure that the sutures used will be able to secure the soft tissue to the bone, surgeons have used suture anchors that affix to the bone, thus securing a portion of the suture to the bone. This is done to increase the likelihood that the soft tissue will reattach itself to the bone surface, rather than being pulled away. In order to use these conventional devices, the surgeon will make a hole in the cortical bone, and insert the suture anchor within the hole. The anchor is designed to secure itself within the cortical bone by exerting some pressure on the cortical bone surface, digging into the bone itself, or any other method that ensures that the anchor cannot be easily extracted from the bone. After the anchor is secured, surgeons use the suture that is attached to the anchor to affix the soft tissue to the bone.
Unfortunately, the level of growth of the soft tissue onto the bone may be limited when using these devices. Some devices are designed so that a large portion of the anchor is within the cortical bone; however a portion of the anchor, along with the suture, sits outside the surface of the cortical bone. The protruding surface will often have contact with the soft tissue that is being sutured to the cortical bone. The irritation caused by the anchor on the soft tissue may prolong, if not hinder, full recovery from the surgical procedure.
Other conventional devices place the entire body of the suture anchor within the hole made in the cortical bone such that the no portion of the device extends beyond the outer surface of the cortical bone into the soft tissue, or beyond the inner surface of the cortical bone into the spongy bone. These suture anchors are placed under stress, as the sutures are pulled from the anchor to the outer surface of the bone. At times, this stress can cause the suture anchor to move, possibly resulting in a portion of the anchor ultimately protruding from the outside surface of the cortical bone, thus causing problems similar to those discussed earlier. Also, such movement of the anchor within the bone further increases the damage that is done to the cortical bone, and increases the likelihood that further treatment will be necessary to correct the injury.
The cortical bone is also capable of mending itself whenever it is damaged. However, similar to the soft tissue surrounding it, the cortical bone must be free from irritations or obstructions to heal quickly and properly. When conventional surgical anchors occupy an opening through the cortical bone, these devices can be causes for irritation, although the bone may grow around the anchor. This may result in increasing the time to full recovery, if not preventing full recovery all together.
Many times, individuals who undergo arthroscopies reinjure themselves in the same joints or other locations. As a result, oftentimes the same arthroscopic procedure must be done multiple times in the same area. Although the bone may heal itself, due to the method of installing these bone anchors, once one is in place, it cannot be removed without incurring further damage to the bone. As a result, if further injury is suffered at the same site, or in a close vicinity to the site where the suture anchor was installed, the previously installed suture anchor cannot be moved to make room for a new one. This reduces the options that are available to the patient for repairing the injuries they suffer.
There are some suture anchor devices that are not designed to occupy a hole through the cortical bone, but rather are designed to pass through the center of the bone, and come out to the other side. Because the anchor is not sitting within the bone itself, the need for small devices is not as much of a concern. By using the distal outer surface of the bone to support the sutures, the need to ensure that the suture anchor is well secured within the bone becomes unnecessary. However, in order to install these devices, it is necessary for the surgeon to drill through both sides of a bone, and then pass this device through the bone to the other side. This maneuver is difficult, if not impossible, in minimally invasive surgeries, such as arthroscopies, as the device must be threaded through the bone and pulled out the other side.
Although this type of anchor does reduce if not nullify the irritation concerns that arise with other conventional suture anchors, the amount of trauma that the installation does to an individual's body is great. There is significant trauma to the bone, as it is necessary to drill through the cortical bone on the side where the device will enter the bone, through the spongy bone, and through the cortical bone on the opposite side where the device will exit the bone. This trauma is further increased by by installing the device after the extensive hole-drilling operations are complete.
In order to install this anchor, the surgeon would have to pass one end of the anchor through the hole, grab the anchor on the other side of the bone, and properly position the device. This sort of device cannot be used in surgeries that are done in very small areas where the opposing side of the bone is not readily visible or accessible during a surgery. Also, in surgeries performed on bones that abut nerves, it would be virtually impossible for the surgeon to install this device without increasing the likelihood of serious injury to the patient. Furthermore, there is much more internal area of the bone that is exposed when this device is used. Unlike in the conventional suture anchors discussed above, this device will leave at least one hole in the bone that is not covered, and exposes the interior spongy bone to the outside. This provides more opportunity for complications from infection to arise.